Key points of burner and boiler combination

Key points of burner and boiler combination
If a fully automatic oil (gas) burner with excellent performance is installed on a boiler, whether it still has the same good combustion performance largely depends on whether the aerodynamic characteristics of the two match. Only with good coordination can the performance of the burner be fully utilized, ensuring stable combustion of the furnace, achieving the expected thermal energy output, and achieving good thermal efficiency of the boiler.
Gas dynamic characteristics matching
A single machine fully automatic burner is like a flame injector, injecting flames into the furnace (combustion chamber) to achieve complete combustion and output heat inside the furnace; The burner manufacturer determines the combustion integrity of the product in a specific standard combustion chamber. Therefore, standard experimental conditions are generally used as selection criteria for burners and boilers. These conditions can be summarized as:
1. Power;
2. Air pressure inside the furnace;
3. The spatial size and geometric shape (diameter and length) of the furnace.
The matching of aerodynamic characteristics refers to the degree to which these three conditions are met.
power
The power of the burner refers to the amount of mass (kg) or volume (m3/h, under standard conditions) that can be burned per hour when the fuel is fully burned, as well as the corresponding thermal energy output (kw/h or kcal/h). The boiler is calibrated based on steam output and fuel consumption. The two must match when selecting.
Gas pressure inside the furnace
In an oil (gas) boiler, the hot gas flow starts from the burner and is discharged into the atmosphere through the furnace, heat exchanger, flue gas collector, and exhaust pipe, forming a fluid thermal process. The hot gas flow generated after combustion flows upstream in the furnace, just like water in a river, with a liquid level difference (water droplets, water head) flowing downstream. Due to the resistance of furnace walls, channels, elbows, baffles, branches, and chimneys to gas flow (referred to as flow resistance), it can cause pressure loss. If the pressure head cannot overcome the pressure loss along the way, the flow rate will not be achieved. Therefore, a certain flue gas pressure must be maintained inside the furnace, which is called the back pressure of the burner. For boilers without induced draft devices, after considering the pressure loss along the way, the pressure inside the furnace must be higher than atmospheric pressure.
The magnitude of back pressure directly affects the output of the burner, which is related to the size of the furnace, the length and geometric shape of the flue. Boilers with high flow resistance require high burner pressure. For a specific burner, its pressure head has a maximum value, which corresponds to the maximum air damper and maximum airflow state. When the intake throttle valve changes, the air volume and pressure also change, and the output of the internal combustion engine also changes. When the air volume is small, the pressure head is small, but when the air volume is large, the pressure head is high. For specific national tigers, when the inlet air volume is high, the flow resistance will increase, which increases the back pressure of the furnace, and the increase in the back pressure of the furnace will suppress the outlet air volume of the burner. Therefore, when selecting a burner, it is necessary to understand whether its power curve matches reasonably.
The influence of furnace size and geometric shape
For boilers, the size of the furnace space is first determined by the selection of the furnace thermal load intensity during the design process, and the volume of the furnace can be preliminarily determined based on this.
After determining the volume of the furnace, its shape and size should also be determined. The design principle is to fully utilize the furnace volume; Try to avoid dead corners, have a certain depth, have a reasonable flow direction, and ensure sufficient reaction time to ensure complete combustion of fuel in the furnace. That is to say, let the flame sprayed by the burner have sufficient residence time in the furnace, because although the oil mist particles are very small (<0.01mm), they have been mixed and ignited before being sprayed out of the burner, but it is not enough. If the furnace is too shallow and the residence time is not enough, incomplete combustion will occur. The lighter exhaust CO exceeds the standard, while the heavier one emits black smoke and the power does not meet the requirements. Therefore, when determining the depth of the furnace, it is necessary to match the length of the flame as much as possible and increase the outlet diameter of the center counter fire type to ensure the volume occupied by the return air.
The geometric shape of the kiln mainly affects the flow resistance of the airflow and the uniformity of radiation. The boiler must undergo repeated debugging to match the burner well.